Beam-calipers



(Model.)

s. H. BBLLOWS.

BEAM GALIPERS.

PatentedMay 13, 1890.

Mlm. lfm MJ .IM ow -W mw m l IH4 m f 9m UNITED STATES PATENT EEICE.

STEPHENQH. BELLOWS, OF ATHOL, MASSACHUSETTS.

B EANl-CALIPERS.

SPECIFICATION forming part of Letters Patent No. 427,956,` dated May 13, 1890.

Application filed December 26, 1889. ASerial No. 334,9@3 (Model.)

To @ZZ whom, it Hwy con/067172,:

Be it known that I, STEPHEN Il. BELLows, a citizen of the United States, residing at Athol, in the county of Torcester and State of Massacliusetts, have invented new and useful Improvements in Open-Faced Beam-Calipers, of which the following' is a specification.

My invention relates to that class of instruments commonly known as beam-calipers, in which the caliper-arms are adjustable upon a graduated beam or rule.

It is the purpose of said invention to provide a simple construction whereby the entire graduated face of the beam shall be visible and available for measurements of every kind, and to provide the adjustable caliperarm with index-marks so arranged with reference to the graduation of the beam that accurate adjustments and measurements may bemade lto the smallest fractional subdivisions of an inch without the necessity of graduating the beam to the highest degree of attenuation, whereby the eye of the user is liable to become confused and the accuracy of adjustment seriously impaired, while the labor and expense of manufacture are materially enhanced.

lt is my object, in short, to provide abeamcaliper having graduations to the ftieth or any other fractional parts of an inch, wherein the face of the adjustable caliper-arm is provided with index marks which may be brought into coincidence with the said graduat-ions alternately, thereby securing adjustments and measurements of exactly half the highest graduations of the beam.

Theinvention consists in the several novel features of construction and new combinations of parts hereinafter fully set forth, and then definitely pointed out in the claims following this specification.

To enable others skilled in the art to make, construct, and use my said invention, l will describe the same in detail, reference being had to the accompanying drawings, in which- Figure l is a front elevation of a beam-caliper embodying my invention. Fig. 2 is a partial elevation, upon an enlarged scale, show-V ing the manner of graduation of the beam and the position of the index-marks upon the caliper-arm with reference to such graduation. Fig. 3 is a transverse section on the line x x, Fig. l. Fig. it is a transverse section showing a slightly-modified construction.

In the said drawings, the reference-nu meral l designates the beam of the calipers, consisting of a flat strip or bar of steel or other material suitable for the purpose. The opposite faces of the beam are parallel, and the longitudinal edges 2 are beveled oppositely toward the face to which the graduations are applied. These graduations are of two kinds, a scale being applied to one edge of the beam containing divisions up to the sixty-fourth part of an inch, while upon the other and parallel edge the divisions are extended to the fiftieth part of an inch only.

Upon the beam l is mounted an arm 3, having a thickness somewhat in excess of that of the beam and provided in its broader end with a dovetailed recess 4, which receives the beam. In the end of the arm below this recess is formed a segmental recess whichreceives a disk 5, carried by a threaded pin 6, which passes through an aperture in the arm and projects from the back side thereof, where it receives a milled nut 7. A portion of the disk 5 is removed, and the straight edge thus formedis beveled to correspond with the bevel of the edge of the beam. By turn-v ing the milled nut 7 the straight beveled edge of the disk may be drawn with considerable force against the edge of the beam, thereby locking the arm vfirmly in position at any point to which it may be adjusted. The other arm S, which may be termed the adjustable arm, is constructed in a manner similar to that described and is locked-by similar means. this arm is mounted a secondary or auxiliary slide 9, having a lock l0, which is the counterpart of the holding device 5 and nut 7. Through an opening l2 in the end of the slide 9 is passed a threaded spindle 13, the end of which is tapped into the rear edge of the arm S, a spiralspring 14 being coiled on said spindle between the secondary slide and the arm. It will be seen that by locking the auxiliary slide 9 in position and operating the spindle by means of a milled nut 15 an Upon the beam in rear of;`

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exceedingly delicate adj ustmen t may be given to the adjustable arm S.

Upon the tlat tace of the arm S, which is flush with the graduated face of the beam, is placed an index-mark 1G, which is exactly one-tenth of an inch from the working-face of the arm. Upon the same face of the arm S, at a little distance from the mark Iii, is placed a separate mark 17, the interval be tween the two bein sneh that when the mark 10 is caused to coincide with one of the divisions of the scale the mark Y17 will st-and exactly hal t`way between two of the graduations marking a division et one-tiftieth et' an inch. It, now, the threaded spindle 13 be opera-ted until said mark 17 is caused to coineide with either of the marks between which it stands, it will be seen that the caliper-arm will have an adjustment of exactly the onehundredth part of an' inch, whereupon the mark 1G will equally divide one of the subdivisions ot the beam.

Upon the foot of the arm S is an index-mark 1S, which coincides with the gradnations ot' the scale to sixty-fourths ot an inch. inasmuch, however, as it is not desirable to divide the sixty-fourth part ot an inch no secondary mark is applied. By this arrangement I am able to secure extremely accurate adjustment to the one-lmndredth part of an inch upon a scale of tittieths of an inch, thereby avoiding the confusion to the eye which niiavoidably arises when the graduation is extremely close. The same principle can be applied to measurements of the two-hundredth part of an inch, &c.,by the addition ot a Iurther differential index mark or marks. A mark lt) is also formed upon the base of the arln 3, one tenth of an inch VIrom the working-face, to correspond to the decimal scale with which said mark must coincide. It will readily be seen that by varying the interval between the index-marks 1li and 17, I may obtain still further fractional measurements. For example, while the second mark is shown in the drawings as placed at a distance from the iirst of nine one-hundredths of an inch I may make this interval ninety-nine one-thousandths of an inch, and thus obtain dil't'erential measurements of the one-thousandth part of an inch without additional grad nations upon the beam. I may also modify the construction ot the beveled edges of; the beamas, forexample, bymakiug them half-round, as shown in Fig. -,l-, orot' any other form which will admit ot a longitudinal adjustment and an exposure of the entire graduated face of the beam, which should be llush, orsubstantially so, with the parts havingcoinciding marks to enable the coincidence to be more accurately determined.

Upon the extremities of the arms J3 and S, I form points il, which may he usedV for inside measurements in the manner already well known.

I do not wish to be understood as claiming herein that which is described and shown by my Letters ,latent No. 4,053,726, issued Mayl, 1889. In the instrument described and shown by that patent the ti ne measurements depend solely on a micrometer measuring-screw without regard to the half-inch graduations on the beam, and in this respect the former instrument is quite dillerent from that herein described and shown.

lW hat I claim is- 1. An open-faced beam-caliper gage consisting of the following elements, to wit: a beam having on one t'ace two linear scales of d itterent subdivisions, a pair of (izalper-arms having one faee arranged. in the plane ot the graduated face of the beam, and one of said caliper-arms provided with a series of indexmarks which, respectively, co-operate, substantially as described, with the two linear scales for the desired fine measurements.

2. An open-faced beam-caliper consisting of a tlat beam or rule having beveled edges and provided with two scalesot dil't'erentsubdivisions of an inch, and caliper-arms adjustable on said beam, one of said arms being provided with index-marks which coincide with the graduations of thebeam alternately as the arm is adjusted, substantially as described.

El. In an open-faced beam-ealil'ier, the combination, with the ilat beam or rule having oppositely-beveled edges and provided upon one flat .lace at or near the edges with two differential graduated scales, of arms having dovetailed recesses to receive the beam, disks having straight beveled edges engaging one edge ol' the beam and provided with spindles operated by nuts, al secondary or auxiliary slide, a thread ed spi ndle con necti n said slide and one ofthe arms, and a spring coiled thereon between the slide and arm, the latter being provided with two indexmarks on its [lat face at the edge, said marks being arranged at such interval that they willcoincide with the graduations alternately, substantially as described.

4. Inv an open-faced beam-caliper, the combination, with a rule having oppositely-beveled edges and provided with differential grad uations upon its narrower face, said graduations extending to the angle of the bevel, of adjustable caliper-arms having dovetailed rccesses which receive the rule, bringing the open faces of said arms substantially flush with the graduated face of the rule, disks lying in recesses in the ends of said arms and having straight beveled edges engaging' the edge ot' the rule and provided with screws receiving nuts, an adj nstable slide, a threaded spindle engaging the slide and tapped into the arm, and a spring coiled on the spindle and [lat .tace ot' one or more ot saidiarms being provided with index-marks which can only coincide with the graduations of the ICO IIO

rule successively or alternately, substantially ations of the rule alternately, substantially as described. as described. 1o

5. In,y an open-faced beamfcalper, the ooln- In testimony whereof I have affixed my sigbination, with a rule having` a series of gradnature in presence of two Witnesses. 5 nations indicating1 the higher fractionaldivis- STEPHEN H. BELLOS.

ions of an inch, of an adjustable arm having Vitnesses: `aiaduations which upon the adjustment of GEO. T. JOHNSON,

:the arm coincide with the successive gradu- OSCAR A. SCOTT. 

